Surgical scalpels or surgical knives which are in commercial use have a handle and a disposable blade. The blade can be detached from the handle and disposed of by deposit in a special container which can thereafter be handled with reduced hazard of sharps injury.
A sharps injury means any cutting or penetrating object that can be reasonably anticipated to penetrate the skin or other part of the body to result in an exposure incident which includes occupational exposure to blood and other potentially infectious materials. Clearly, this covers scalpels and other types of surgical knives.
The commercially available scalpels which have a disposable blade generally have reusable handles. The handle can be sterilised by autoclaving and reused, and these handles are usually formed from metal.
The surgical blade comes packaged in a protective foil. The foil is carefully opened to expose the blade. The blade is then held between thumb and finger and carefully attached to an extending projection of finger on the handle. Upon completion of the surgical procedure, the blade is either manually detached from the handle and placed in a sharps bin, or the handle with the blade is inserted into a container which breaks off the blade.
It can be seen that attachment of the blade to the handle is a hazardous procedure and can easily result in a sharps injury. If the blade is manually detached, this can also result in a sharps injury which is even more hazardous as the blade may be contaminated.
During surgical use, the scalpels can accidentally cut the surgeon's fingers, or the fingers of nurses and other support persons in the operating theatre. As well, operating personnel can be accidentally cut when the scalpel is passed between personnel.
To partially mitigate against accidental sharps injuries in handling the scalpel, it is known to provide a retractable blade guard. The blade guard is attached to the handle, and can be manually pushed between an extended blade guarding position, and a retracted blade exposed position Thus, blade guards attached to scalpel handles are known.
These blade guards have some disadvantages. Firstly, by being part of the handle, the handle must be thoroughly cleaned from any blood and tissue after use, if the handle is to be reused. The blade guard can catch and contain tissue, congealed blood, and the like in the various nooks and cavities in the blade guard and it is extremely difficult to ensure that the blade guard is absolutely spotlessly clean to allow the handle with the attached blade guard to be reused. To allow the handle to be reused many times, the blade guard must be fairly robust and this can result in the guard being of fairly complex manufacture, quite bulky, and quite expensive.
A second disadvantage with this arrangement is that the blade guard cannot protect against initial attachment of the sterile blade to the handle. That is, the blade guard must be fully retracted to expose the projection or finger on the handle to which the blade is attached. The blade must be attached in the usual manner which is to initially remove it from its protective foil and then physically attach it to the handle. Thus, existing blade guards do not reduce or eliminate sharps injuries which can result in initial attachment of the blade. As well, these guards do not protect against removal of the blade from the handle.
Our earlier international patent application WO 01/05312 described a surgical scalpel with a retractable guard. The device overcame many of the above-mentioned disadvantages.
However, attachment of the blade to the handle could still risk a sharps injury especially if the person attaching the blade was inattentive or very junior.
With larger blades and handles there was the possibility that the guard could “pop off” the handle when retracted due to some flexibility in the larger guard.
It was also possible to pull the guard back too far and to pull the guard off the handle.
When the guard was retracted to expose the blade and extended to cover the blade, there was the possibility of insufficient retraction and extension which could cause a portion of the blade to be exposed [with insufficient extension] or only partial exposure of the blade cutting edge [with insufficient retraction]. It was also possible for the guard to inadvertently move during use. Thus a visual check was needed. However there would be an advantage if the fully retracted position and the fully extended position could be sensed without constant visual checking, and/or if these positions could be lightly “locked” in place.